Drawing-table



E. R. KOECHLIN.

DRAWING TABLE.

APPLICATION FILED OCT-5| |9l8-- I I Inventor: 6% AW er i, WW 1 Attorney.

Patented J an. 13, 1920.

" as rarer orrroe.

EMILE RAYMOND KOECHLIN, OF AMSTERDAM, NETHERLANDS, ASSIGNOR TO NAAMLOOZE VENNOOTSCHAP WEDUWE J. AI-IREND 85 ZOONS INDUSTRIE EN HANDELSVEREENIGING, OF AMSTERDAM, NETHERLANDS, A COMPANY OF THE NETHERLANDS.

DRAWING-TABLE.

Specification of Letters Patent. Patented J an; 13, 1920.

Application filed October 5, 1918. Serial No. 257,038.

To all whom it may concern:

Be it known that I, EMILE RAYMoND KOEOHLIN, residing at Amsterdam, in the Kingdom of the Netherlands, have invented certain new and useful Improvements in Drawing-Tables, of which the following is a specification. I

My present invention relatesto a drawing table of the type comprising a drawing board connected with two adjacent joints of an articulated parallelogram guide the third joint of which forms a fixed fulcrum and is connected with the board by a link which extends beyond said fulcrum and is providedwith a counterweight for counterbalancing the board, whereas the fourth joint is pivoted to a member whose freedom of motion is counteracted by a suitable friction device.

My invention is designed to provide improved means for preventing the four joints of the parallelogram guide from moving into one straight line, which would mean a dead or center position of the link mechanism.

My invention will be best understood by reference to the accompanying drawing, which will now be described, it being understood, however, that various changes may be made in the details of construction and arrangement by those skilled in the art, without departing from the spirit and scope of my invention.

In the drawing:

Figure l is a side elevation of my improved drawing table, and Fig. 2 a diagrammatic view illustrating the link mechanism on a larger scale after two of its sides have been moved into alinement, it being understood that in Fig. 2 certain parts are omitted and the difierence of said mechanism from a parallelogram is somewhat exaggerated for the sake of clearness.

Referring to the drawing, the numeral 1 designates the drawing board which is connected in a known manner with an articulated link mechanism the joint 2 of which forms a fixed fulcrum, the joint 3 being hinged to a rod l which is slidably mounted in a tube 6 having its pivot at 5. The freedom of motion of the rod 4 within the tube 6 is counteracted by a suitable spring friction device not shown in detail.

Now, according to my present invention,

the link mechanism has a form which slightly difiers from. a parallelogram, that is to say that the sum of the lengths of the sides a and b is say one eighth of an inch, or so much more or less as may be convenient, greater than that of the sides 0 and d. This being so, it is clear that, if the drawing board is caused to move from the position shown in Fig. 1 in such a manner that the apex ofthe angle between the levers c and (Z remains stationary, the sides 0 and (i will have moved intoalinement while the sides a and 6 still inclose an angle of less than 180 (see Fig. 2), so that a further movement toward a wholly collapsed position is impossible. I

My improved drawing table has obviously quite the same advantageous features as a drawing table wherein the link mechanism has exactly the form of a parallelogram, as the change effected in the form of said mechanism does not prevent the board from assuming positions substantially parallel with each other.

Having thus fully described my invention, I claim as new and desire to .protectby Letters Patent of the United States:

1. In a drawing table, including a movable drawing board and a support, guiding means adapted to permit said board being displaced into positions parallel with each other, said means comprising an articulated quadrilateral pivoted both to said table and said support, the sum of the lengths of two adjacent sides of said quadrilateral being slightly greater than that of the other two sides. I

2. In a drawing table, the combination of a drawing board, cn' articulated quadrilateral having two adjacent joints connected thereto, said quadrilateral having substantially the shape of a parallelogram, a sup port carrying another joint thereof, and a pivoted member carrying the fourth joint of said quadrilateral, the sum of the lengths of two adjacent sides of said quadrilateral being slightly greater than that of the opposite sides.

In testimony whereof a'lfix my signature.

Witnesses: I

D. KLEYN, M. ALVARADO. 

